Heat generating apparatus are normally cooled by a forced air flow driven by fan means. It is therefore necessary to position these heat generating apparatus so that they can be reached effectively by the flow of air from the fan means.
Radio transceiver units are positioned primarily to satisfy radio coverage requirements to the best possible effect. This often means that the radio transceiver unit must be mounted on a mast, on a roof, at the top of a wall structure or in some other place that is not easily reached. In those cases when heat radiation, caused by power dissipation in the transmitter, is high, a higher cooling effect is also required. A bulky and/or heavy fan means is required to produce a cooling effect of this required magnitude. When radio transmitter equipment is placed in a radio mast or some like structure, it must be assumed that the equipment is highly reliable, since it will be difficult to reach for repair and maintenance work, due to its high location. Naturally, it is also necessary to reinforce the mechanical strength of the mast to an extent commensurate with the increase in capacity of the cooling unit. When the radio transceiver unit is mounted in, on or above a building structure, it must be ensured that the bearing capacity of the structure and the space afforded will be sufficient to meet requirements.
From the aspect of radio coverage, it is thus desirable that the radio transmitter has a high permitted power output, which will probably result in high dissipation powers and significant heat radiation from the transceiver unit. At the same time, it is also desirable to use a reliable radio transceiver unit of low weight and small volume, for economic and aesthetic reasons. These requirements would seem to be incompatible with respect to known technology.